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ENERGY & CARBON
Hello! Welcome to my new article. Today I wanted to talk to you about the carbon content of different energies… Hold up! What’s that, you say? No worries, it’s very easy to understand. Let me explain.
Carbon content is simply the amount of greenhouse gas emitted by every human activity, and it is expressed as CO2 equivalent by kilowatt-hour (KWh). In short, the smaller this number, the better! Let me introduce you to the carbon content of different energies.
Nuclear energy is not renewable, because its production requires a fossil fuel, uranium, a radioactive metal found in the Earth’s subsurface. It allows for the production of electricity in thermal nuclear plants, called electronuclear plants, thanks to heat created by the fission of uranium atoms. Its carbon content is quite low (16g CO2 eq/kWh median value). However, it generates radioactive waste, over very long periods of time, that are complex and knives to manage.
Photovoltaic solar energy is generated from solar radiation. Each year, it produces 20 times the global electricity needs. Yet, it still represents only 1% of the global electricity production capacity. The energy produced by photovoltaic solar plants is renewable, because its source is considered inexhaustible, at least on a human timescale. Therefore, even though the production, installation, and exploitation of photovoltaic solar panels mostly require non-renewable energies, a photovoltaic systems will generate between 20 and 40 times more energy than what was used to built it, for a median carbon content of about 46g CO2eq/kWh.
Natural gas is a fossil fuel naturally present in gas form in porous rocks found in the Earth’s subsurface. It is generated from the sedimentation of millions of years old organic matter. It contributes to about 20% of electricity production. Considered to be a flexible, efficient, and easy-to-use fuel, it can be stored and transported. When combusted, the gas generates, in equivalent energy production, about 3 times less CO2 than coal, even though it still produces more CO2 than the other types presented here.
Coal is a sedimentary rock exploited as a fuel in collieries and formed from the partial decomposition of organic matter. To meet the goal of international negotiations on climate to maintain the temperature increase below 2°C compared to the preindustrial era, we would have to globally abstain from extracting over 80% of the available coal in the Earth’s subsurface before 2050. Indeed, coal is the most carbonaceous energy source.
Wind power is generated from winds whose force is transformed with an aero generator device, like a wind turbine. To produce electric energy, the wind turbine is then coupled with an electric generator to generate alternative or direct current. The generator is linked to an electric network or works within an “autonomous system” with a stand-by generator and/or a battery system or another energy storage device. This energy source is among the least carbonaceous of the list, above hydroelectric energy.
Hydraulic energy allows for the production of electricity, in hydroelectric plants, with the force of water. This force depends of the height of the waterfall (high or medium head) or the river flow (run-of-river plants). It’s the type of energy that emits the least greenhouse gas, it is quickly usable thanks to large water quantities stored, and it is a very economical renewable type of energy on the long term.